Painting one wind turbine blade black cut bird deaths by 74% at a Spanish wind farm

Painting one of the three blades on a wind turbine black reduced bird deaths by 74% at a wind farm in southern Spain, according to a study published in Ecology and Evolution. The experiment ran from 2012 to 2024 at the El Ruedo wind farm in Cádiz.

Thirteen years of daily carcass searches

Researchers painted one blade black on four of the farm's 20 turbines. Teams searched daily for dead birds under the turbines for 9.5 years before the paint went on and 3.5 years afterwards, comparing the painted turbines with unpainted ones.

Bird deaths at the painted turbines fell by 74% relative to the unpainted controls. The biggest drop was in small songbirds and large waterbirds; the effect on birds of prey was smaller.

The black blade breaks up the blur

Fast-spinning white blades can blur into the background, making them hard for birds to see. A contrasting blade is meant to make the rotor more visible. The idea was first tested at the Smøla wind farm in Norway, where one black blade cut annual bird deaths by more than 70%, according to that 2020 study by the same lead author, Roel May.

The Spanish results show the measure works at very different latitudes and with different bird communities. The authors say it is now "paramount" to overcome the hurdles to putting the measure into wider use.

Questions remain about which birds benefit most

The study involved only four painted turbines at one site, and the researchers say it is still unclear how local bird numbers, flight behaviour and differences in bird vision affect how well the measure works. Wind power keeps growing, as shown by the world's tallest wind turbine in Germany, so simple ways to protect birds matter.